I am getting ready to start testing my tube fabrication process. It will be a wet lay up and room temperature cure. I am still on the fence about what kind of vacuum to get, but I happen to have a hand held vacuum pump that will get about 25-26 inches of vacuum, and was considering using it for my testing. Is 25 inches enough? If not, what value is considered the minimum for bagging CF?
What altitude are you at? That will have a play in your maximum vacuum…
25-26 would be about right if you’re 4000-5000 feet above sea level (based off my chart).
900 feet, although the question might be moot now. I just spotted a new offshore vacuum pump on sale at an auto parts supply company here in town. $190 for a new 3cfm machine one year warrantee rated 150 microns, which one table says is about 29.9 inches of mercury.
That will be sea level. Just under 1000 feet, your max vac will be just under 29.
Hmmm… My first experience with the new vacuum did not go well. It was a factory sealed box, and I followed the instructions explicitly. The first clue that all was not right came when I poured about 7 ounces of oil in, and the level did not change. I poured the last ounce in and it still did not change, even though the capacity is 8 ounces. I then ran the pump with closed connections for the recommended two minutes. It did not sound healthy. I then tried the vacuum with a gauge. It pulls about 27 inches, which is less than it should, and I think the oil has escaped into another part of the machine, because it still does not register in the gauge.
No idea of your system, but the oil should be seen in the sightglass. (and should be about half-way of the glass or upper glass, unless otherwise stated).
Stupid question: you did put the oil in the fill cap stating “oil” did you?
And then for a fun video:
[ame=“http://www.youtube.com/watch?v=Rjd7Kx_jO3o”]Blond meisje vult olie bij - YouTube[/ame]
Yes, the cap is well marked. There is a clearly marked sightglass that showed a very small amount of oil when unboxed, and this level did not change after adding oil. The company ordered another one and I will be exchanging it tomorrow.
Indeed strange.